A wide variety of implantable medical devices (IMDs) are available for monitoring physiological conditions and/or delivering therapies. Such devices may include sensors for monitoring physiological signals for diagnostic purposes, monitoring disease progression, or controlling and optimizing therapy delivery. Examples of implantable monitoring devices include hemodynamic monitors, ECG monitors, and glucose monitors. Examples of therapy delivery devices include devices enabled to deliver electrical stimulation pulses such as cardiac pacemakers, implantable cardioverter defibrillators, neurostimulators, and drug delivery devices, such as insulin pumps, morphine pumps, etc.
IMDs are often coupled to medical leads, extending from a housing enclosing the IMD circuitry. The leads carry sensors and/or electrodes and are used to dispose the sensors/electrodes at a targeted monitoring or therapy delivery site while providing electrical connection between the sensor/electrodes and the IMD circuitry. Leadless IMDs have also been proposed which incorporate electrodes/sensors on or in the housing of the device.
Physical connection of an IMD to sensors implanted deeply in a patient's body or distributed in various body locations to enable communication of sensed signals to the IMD can be cumbersome, highly invasive, or simply not feasible depending on a desired sensor implant location. Furthermore, as sensors become miniaturized to facilitate minimially-invasive surgical methods and implantation at very specific monitoring sites, the power capacity of such sensors becomes limited due to physical size of the sensor. As implantable device technology advances, and the ability to continuously and remotely provide total patient management care expands, there is an apparent need for providing efficient wireless communication of data acquired by implantable physiological sensors.